Ratchet mechanism for charging a closing spring in an electric circuit breaker



April 2, 1963 R. J. BASKERVILLE RATCHET MECHANISM/FOR CHARGING A CLOSING SPRING IN AN ELECTRIC CIRCUIT BREAKER 3 Sheets-Sheet 1 Filed Nov. 3. 1960 Inventor: Ralph J. Baskerville,

b QUMYS. Atto'r'ne April 2, 1963 R. J. BASKERVILLE 3,084,238

RATCHET MECHANISM FOR CHARGING A CLOSING SPRING Filed Nov. 3, 1960 IN AN ELECTRIC CIRCUIT BREAKER 5 Sheets-Sheet 2 Inventor: Ralph J. Baskerville,

b5 aQQN-ck S.

Attorney.

Apri 1963 R- J. BASKERVILLE RATCHET MECHANISM FOR CHARGING A CLOSING SPRING IN AN ELECTRIC CIRCUIT BREAKER 3 Sheets-Sheet 3 Filed Nov. 3. 1960 Inventor:

Ralph J.Baske1-vil|e, b Ms. W Attorney.

RATCHET MEtIHANlSM FOR CHARGENG A CLOSING SPRING IN AN ELECTRIC ClRCUlT BREAKER Ralph J. Baskerville, Drexel Hill, Pm, assignor to General Electric Qompany, a corporation of New York Filed Nov. 3, 1960, Ser. No. 67,087 Claims. (C1. 2011-153) This invention relates to an improved ratchet mechanism for manually charging a closing spring in an electric circuit breaker.

In a copending patent application S.N. 63,802, Baird, filed on October 20, 1960, and assigned to the assignee of the instant application, there is disclosed and claimed a double-pawl ratchet mechanism for charging a closing spring in an electric circuit breaker. In accordance with that disclosure, the ratchet mechanism comprises a rotatable ratchet member connected to the closing spring to stress the spring upon rotation of the member, and a pair of reciprocating pawls are disposed to rotate the member upon operation thereof. The pawls are operated by a conveniently disposed oscillatory handle, and by pumping the operating handle an operator can efifect step-by-step advancement of the ratchet member thereby charging the closing spring. It is an object of my invention to provide certain improved features in the above-described ratchet mechanism.

A more specific object of the present invention is the provision, in a ratchet mechanism for charging the closing spring of an electric circuit breaker, of improved means for interconnecting the rotatable ratchet member and the closing spring without the necessity of relatively complex and expensive linkages.

Another object of this invention is to provide an improved, safer circuit breaker in which inadvertent movement of an oscillatory operating handle, which is provided for manually closing the breaker contacts, is prevented.

A general object of the invention is to provide an improved ratchet mechanism structure of the character described hereinafter.

In carrying out my invention in one form, the ratchet mechanism is arranged to charge a circuit breaker closing spring having an arcuately movable spring retaining member associated therewith. The ratchet mechanism includes a rotatable ratchet wheel having an eccentric output element orbitally movable in a plane which intersects the plane of arcuate movement of the spring retaining member. The output element and the spring retaining member are interconnected by means including a bearing having a spherical camm-ing surface, whereby the retaining member is moved and the spring is stressed in response to rotation of the wheel. In order to rotate the ratchet wheel, a pair of reciprocating pawls are disposed to engage peripheral teeth formed in the wheel. The pawls are pi-votally mounted on dilferent eccentric portions of an operating member disposed for oscillatory movement, whereby the pawls are alternately eifective to advance the ratchet wheel in response to oscillations of the operating member. A pair of disc-like guide members are disposed on the ratchet wheel to define with predetermined peripheral teeth an annular track in which one of the pawls engages said predetermined teeth. :1 provide bias means for the operating member arranged yieldably to oppose movement of this member at either limit of its oscillations.

My invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevation of a circuit breaker equipped with a stored energy closing mechanism and a manually operable charging means for the closing mechanism, the charging means being constructed in accordance with the improvements of my invention;

FIGS. 2, 3 and 4 are a series of enlarged and exploded front views of the charging means of FIG. 1 showing, respectively, the ratchet wheel of the charging means in three diflerent positions corresponding to early steps in the charging operation; and,

FIG. 5 is a partially exploded front view of a ratchet wheel of modified construction.

Referring now to FIG. 1, the schematically illustrated electric circuit breaker is seen to include a pair of separable switch contacts 11 and 12 connected in a circuit 13 in order to open and close that circuit. One switch contact 12 is carried by a movable switch arm 14 between an open circuit position, in which it is shown in FIG. 1, and a closed circuit position in which it is engaged by the other switch contact 11. The movable switch arm 14- is pivotally supported at 15 and is biased by a suitable opening spring 16 to an open position corresponding to the open circuit position of the switch contact 12.

For actuating the switch arm 14, and hence moving the switch contact 12 to its closed circuit position, I have shown in FIG. 1 a conventional trip-free operating mechanism comprising a pair of toggle links 17 and .18 pivotally joined together at a knee 19. One toggle link 17 is pivotally connected to the movable switch arm 14, whereas the other toggle link 18 is connected by pivot pin 20 to the upper end of a guide link 21. The guide link 21 is pivotally supported at its lower end by a fixed iulcrum 2.2. The pivot pin 2t} carries a latch roller 23 which cooperates with a suitable trip latch 24.

So long as the trip latch 24 remains in the latched position shown, the toggle 17, 18 is capable of transmitting thrust to the movable switch arm 14. Thus, when its knee 19 is lifted from the position shown in FIG. 1, the toggle 17, 18 is extended thereby driving the switch contact 12 toward its closed circuit position. This lifting of the toggle knee is accomplished by the action of a rotatable cam 25 operatively coupled to a roller 26 which is mounted on the knee 19. Preferably, the closing cam 25 is arranged to drive the toggle slightly overcenter and against a stop 27 so that the switch contact 12 will be held in closed circuit position even when the cam is returned to its original position shown in FIG. 1.

Should the latch 24 be tripped when the breaker is closed, or even during the closing operation, the toggle 17, 18 will be rendered inoperative to transmit thrust to the movable switch arm 14. As a result, the opening spring 16 impels the switch contact 12 to its open circuitposition. As long as the latch 24 is held tripped, the toggle 17, 18 will remain inoperative to transmit closing thrust to the movable switch arm 14. The latch may be tripped by any suitable means, as, for example, by energizing the winding of the solenoid 28 illustrated in FIG. 1. A suitable resetting spring 29 cooperates with the guide link 21 to reset the mechanism to the latched position after it has been tripped.

In order to rotate the closing cam 25 so as to actuate the switch arm 14 and drive the contact 12 to its closed circuit position, a stored energy closing device is provided. As is seen in FIG 1, this device comprises a heavy compression spring 36* suitably supported at its upper end by a pivotally mounted bracket 31. Each end of a pin 32 transversely extending from opposite sides of the bracket 31 is disposed in a vertically elongated slot 33 located in a rigid frame member 34 of the circuit breaker. The lower end of the spring 311 is supported by an arcuately movable spring retaining member 35', and a rod 36 extending vertically through the spring 30 is aflixed to the upper portion of member 35. The spring retaining member 35 is pinned at 37 to a crankarm 38 which in turn is keyed to a rotatable load operating shaft 39 suitably journaled in the frame member 34 of the breaker. The previously mentioned closing cam 25 is also keyed to shaft 39.

In FIG. 1 the. spring 30 is shown in a compressed state.

, In other words, the spring, as shown in FIG. 1, is fully charged and breaker closing energy is stored therein. Upon release of the closing energy (which occurs in a manner described hereinafter) the spring force drives the spring retaining member 35 downwardly in an arcuate path thereby rotating the load operating shaft 39 in a clockwise direction, as viewed in FIG. 1. This produces rotation of the closing cam 25 of the mechanism in a manner to actuate the switch arm 14, whereby a high speed and forcible closing operation of the circuit breaker is obtained.

, In order to charge manually the closing spring 30 of the stored-energy closing device, a double-pawl ratchet mechanism is provided. The ratchet mechanism includes a rotatable ratchet member, to be referred to hereinafter as the ratchet Wheel, and this member is identified generally by the reference number 40 in the drawings. The ratchet wheel is supported by a sleeve bearing 41 or the like'for 360 degrees rotation about its axis 4%.. The sleeve bearing is housed in a stationary mounting block 42 which, as is shown in FIG. 1, is secured to the front of the circuit breaker frame member 34-. Projecting rearwardly from the ratchet wheel 40' is an eccentric output element 43 which is connected to the spring retaining member 35 of the stored-energy closing device by means including a self-aligning bearing 44 having a spherical camming surface. The bearing 44 is attached to the output element 43 and is snugly disposed between a pair of spaced, horizontally oriented plates 45a and 45b of the spring retaining member 35.

, As is indicated most clearly by FIGS. 1 and 2, the output element 43 moves orbitally, upon rotation of the ratchet wheel 40, in a plane which intersects at substantially a right angle the plane of arcuate movement of the spring retaining member 35. The spherical camming surface of bearing 44 in cooperation with the flat surfaces of plates 45a and 45b provide a low-friction joint particularly well suited for directly translating the orbital motion of the output element 43 into arcuate motion of member 35. This feature of my invention enables a direct connection to be made between the element 41 and the member 35 even though these two parts undergo curvilinear motion in non-parallel planes, and more complicated and expensive interconnecting linkages are eliminated.

The closing spring 30, acting through its associated retaining member 35 and the eccentric output element 43 connected thereto, normally biases the ratchet wheel 40 to a first angular position in which it is shown in FIG. 2. Here the output element 43 is at the lowest point in its orbit, and the spring 30 is in a relatively extended state. The spring will be stressed and closing energy is accumulated therein upon rotation of the ratchet wheel 40 to a predetermined second or top dead-center position wherein the output element 43, as is shown in FIG. 1, is at its apogee. V

For the purpose of rotating the ratchet wheel 40, a plurality of peripheral teeth are formed therein. Preferably these teeth are arranged in two sets disposed in sideby-side relationship, each set comprising four teeth. In FIGS. 2-4 the successive teeth of one set are identified by the reference numbers 51, 53, 55 and 57, respectively, and the successive teeth of the other set are identified by the reference numbers 52, 54, '6 and 58, respectively. The peripheral teeth 51-58 are sequentially engaged for effecting step-by-step advancement of the ratchet wheel 40 from its first position (FIG. 2) to its second or top dead-center position (FIG. 1) by a pair of reciprocating pawls 59 and 60 operated alternately by a pivotally supported oscillatory member 61. The pawls and teeth are so arranged that the ratchet wheel 40 is angularly advanced in a counterclockwise direction as viewed in FIGS. 2-4.

The oscillatory operating member 61 comprises a horizontally oriented shaft suitably journaled in the mounting block 42 and terminated at its forward end, in front of the circuit breaker escutcheon 62, by a conveniently accessible .pistol grip handle '63. The handle 63, which moves in a plane substantially perpendicular to the plane of movement of the circuit breaker switch arm 14, is designed for manual operation between a first or lowered position (FIGS. 1, 2 and 4) and a second or raised position (FIG.

.3) located about 120 angular degrees in a counterclockwise direction from the first position.

In accordance with one feature of my invention, the operating member 61 has associated therewith suitable bias means for urging this member in a counterclockwise direction, as viewed from the front of the circuit breaker,

7 .when the handle 63 is in its raised position (FIG. 3) and alternatively for urging the member 61 in a clockwise direction when the handle 63 is in its lowered position (FIG. 2). Preferably the bias means comprises a compression spring 64 disposed between a stationary bracket 65 mounted on the breaker frame and a radially projecting element 66 keyed to shaft 61. A rod-like spring guide 67 is pinned at one end to the projection 66 and slides freely at its other end in a cooperating slot located in the bracket 65. With this arrangement a toggle-action bias is obtained, whereby the spring 64 is able yieldably to oppose counterclockwise movement of the operating handle 63 away from its lowered position and also to oppose clockwise movement of the handle 63 away from its raised position. The purpose of this two-way bias will become apparent when the operation of the FIG. 5 embodiment of the ratchet mechanism is described hereinafter.

The rear end of the operating handle shaft 61 is provided with two eccentric portions 68' and 69 disposed on opposite sides of the shaft axis, and the pawls 59 and the eccentrics are so disposed on shaft .61 that counterclockwise movement of the operating handle 63, while -carrying pawl 60 to the left and downward, will cause the pawl 59 to move to the right and upwardly thereby partially rotating the ratchet wheel 40, whereas the reverse or clockwise movement of the operating handle 63,

while carrying pawl 59 to the left and downward, will cause the pawl 60 to move to the right and upwardly thereby further rotating the ratchet wheel 40. Thus the pawl 59 is moved to effect angular advancement of the wheel 40 by alternate strokes of the operating handle (upstrokes), and the pawl 60 is moved to effect similar advancement of the wheel by intermediate strokes of the handle (downstrokes).

Pawl 59 is biased into engagement with one set of peripheral ratchet teeth (51, 53, 55 and 57) by means of an appropriate tension spring 71 connected thereto, while pawl 60v is biased into engagement with the other set of peripheral ratchet teeth (52, 54, 56 and 58) by means of another tension spring 72. The wheel-driving end of pawl 60 is disposed in an annular track defined by two spaced-apart disc-like guide members or plates 73 and 74 disposed at opposite sides of the associated set of peripheral teeth. The guide members 73 and 74 are each affixed to the ratchet wheel by appropriate means such as rivets (not shown), and they serve to limit sidewise movement of pawl 60 so that this pawl will not slip off the periphery of the ratchet wheel 40' during operation of the mechanism. 7

Sidewisemovement of pawl 59 is limited in a like manner by the guide member 73 in cooperation with the part of the breaker frame disposed immediately in front of the ratchet wheel. 1 Since the space between member 73 and the breaker frame is more than twice the width of the pawl 59, suitable spacers, such as the illustrated rivets 75 and 76 with protruding heads, have been attached to pawl 59. In this manner the pawl 59' is prevented from slipping off the one set of peripheral teeth (51, 53, 55 and 57) which it engages during operation of the ratchet mechanism.

It will be observed in FIGS. 2-4 that the peripheral teeth 51-53 on the ratchet wheel 46 are not uniformly spaced from the axis 40a of wheel rotation. By disposing the teeth at a plurality of different predetermined distances from the axis of rotation, as shown in the drawings, a special ratchet mechanism operating characteristic is realized. This special operating characteristic and the illustrated manner in which it is obtained will now be explained in detail.

It will be apparent to those skilled in the art that the 'force required to stress the closing spring 30 of the circuit breaker during a spring charging operation increases linearly in accordance with the amount of spring C0111- pression. In other words, the force exerted by the spring 30 on the spring retaining member 35, which member is lifted from its lowest position (FIG. 2) in order to compress the spring, increases directly in proportion to the distance which the spring has been shortened or deflected. As has already been described, it is the orbital movement of the eccentric output element 43 of the ratchet wheel 40 that lifts the spring retaining member 35 thereby charging the closing spring. Accordingly, it is apparent that during the charging operation the output element 43 experiences a downwardly directed force which increases substantially linearly in accordance with its vertical displacement, that is in accordance with the vertical component of movement of element 43 as measured from its initial position shown in FIG. 2. This relationship can also be expressed in'terms of the angular advancement of the ratchet wheel 40': the spring force which bears on the element 43 is a constant-minus-cosine function of the angular position of the ratchet wheel measured with respect to its initial or first position (FIG. 2).

The downwardly directed force acting on the spherical bearing 44 of element 43 during the spring charging operation produces a torque in the ratch wheel 40 opposing its counterclockwise advancement. The magnitude of this torque is, of course, the product of the magnitude of the force and the length of its moment arm. The line of action of the spring force on element 43 is nearly vertical, as viewed in the drawings, and its moment arm is equal to the horizontal displacement of the element 43 with respect to the vertical reference line 77 shown in FIG. 2. Thus, the moment arm of the spring force applied to the element 43 is a sine function of the angular position of the ratchet wheel 40. The spring-produced torque, which is opposing counterclockwise rotation of the ratchet wheel during the charging operation, is consequently a complex function of the angular advancement of the wheel 40, the maximum spring-produced torque being realized when the wheel has been rotated from its initial position to an angular position approximately 120 degrees therefrom.

Rotation of the ratchet wheel 40, for the purpose of charging the breaker closing mechanism, is accomplished by manual operation of the oscillatory handle 63. Through the action of the reciprocating pawls 59 and 60 in cooperation with the eight peripheral teeth 51-58, the operation of handle 63 produces suflicient counterclockwise driving torque in wheel 40 to overcome the springproduced torque discussed above, whereby the closing spring 30 is compressed and breaker closing energy is stored therein. Although the driving torque required to rotate the ratchet wheel varies as the wheel advances, for reasons just explained, the ratchet mechanism is designed so that the force needed to operate the handle 63 does not correspondingly vary during the charging operation. More specifically, the increasing force characteristic of the closing spring 30, as it is incrementally stressed in respouse tostep-by-step rotation of the ratchet wheel, is so compensated by the mechanism construction that repeated oscillations of the operating handle 63- can be effected with the application of a relatively uniform amount of force. As a result of this leveling characteristic of the ratchet mechanism, the breaker closing mechanism can be manually charged with relative ease and dispatch by an operator exerting only a reasonable amount of force to etfect each stroke of the handle 63.

Preferably the relatively-uniform-manual-force operating characteristic of the ratchet mechanism is obtained by appropriately selecting the different predetermined distances at which the various peripheral teeth 51-58 are respectively spaced from the axis of the ratchet wheel 40. The pawls 59 and 60 which sequentially engage the peripheral teeth are thus given variable lever arms, with respect to axis 4tla, and 'the mechanical advantage of the pawl-and-tooth driving means for the ratchet wheel 40 is changed in accordance with the angular position of the wheel. In practice, the peripheral teeth can best be located on the ratchet wheel by graphical methods within the mechanical skill of the art, it being understood that ideally the lever arms of the pawls 59 and 60, as they engage successive teeth 51-58, should vary in the same relationship to the angular position of the wheel as the spring-produced torque varies. As a result of this construction, variations in the manual force needed to effect successive upstrokes and downstrokes of the operating handle .63 during the charging operation are minor compared to the relative increase in the force being exerted by the closing spring 30.

Additional ease of operation of the manually operable ratchet mechanism has been realized by so designing the mechanism that less force is required to effect an upstroke of the operating handle 63 than is required to effect the preceding downstroke. This desirable result is obtainable in the illustrated mechanism by appropriately selecting the spacings, from axis 461:, of the ratchet teeth 53, 55 and 57 in relation to the teeth 52, 54 and 56, respectively.

From the foregoing detailed description of the structure and arrangement of] the illustrated ratchet mechanism, its mode of operation may now be readily followed. In FIG. 2 the mechanism is shown in its initial position with the closing spring 30' discharged, and the operating handle 63 is in a vertical position as shown. An operator performs the first step of the spring charging operation by twisting the handle 63 in a counterclockwise direction through degrees to its raised position. This upstroke of the operating handle causes pawl 59 to push against peripheral tooth 5-1 thereby driving the ratchet wheel 40' in a counterclockwise direction through an angle of about thirty degrees to the position in which it is shown in FIG. 3. The resulting movement of the eccentric output element 43 lifts the spring retaining member 35 to begin the compression of the closing spring 30*.

The second step in the spring charging operation is performed by returning the operating handle 63 to its initial vertical position. This downstroke causes the operating shaft 61 to rotate in a clockwise direction, and pawl 69 coacting with the peripheral tooth 52 drives the ratchet wheel 40 further in the counterclockwise direction to the position in which it is shown in FIG. 4. At the same time the pawl 59 is pulled into a position in which it engages the next peripheral tooth 53. The closing spring 30 is further compressed as a result of the upward movement of the output element 43 during the second step of the operation.

To perform the third step of the spring charging operation, the operating handle 63 is again twisted in a counterclockwise direction to its raised position, whereby pawl 59, acting this time on through peripheral tooth 53, propels the ratchet wheel 40' through an additional counterclockwise angle and the spring is further compressed. This action is accompanied by the resetting of pawl 60 into engagement with the next peripheral tooth 54. Upon returning the operating handle to its initial position during the fourth step of the operation, the pawl 60, acting through tooth 54, drives the wheel further in the counterclockwise direction, and still more energy is stored in the closingspring.

The fifth and sixth steps of the spring charging operationare accomplished by again oscillating the operating handle63, whereupon first the pawl 59 in cooperation with perpiheral tooth 55, and then the pawl 60 in cooperation with peripheral tooth 56, operate to further ad- Vance the ratchet wheel 40 and incrementally stress the closing spring. The seventh step of the charging operation is an upstroke of the operating handle 63 which results in the operation of pawl 59, in cooperation with peripheral tooth 57, to drive the ratchet wheel 40 further in the counterclockwise direction. The closing spring 30 is now almost tlully charged.

The eighth and final step in the spring charging operation is a downstroke of the operating handle 63. Pawl 60 is now in driving engagement with peripheral tooth 58, and during this final stroke (but before its conclusion) the ratchet Wheel is advanced to a position 180 degrees from its initial position, this position being the top deadcenter position of the ratchet wheel. The closing spring 30 is now fully charged.

The illustrated mechanism is designed so that the ratchet wheel is actually driven beyond its top dead-center position during the final downstroke of the operating handle 63, and as a result the spring retaining member 35 is able to reverse its movement and the closing spring 30 is free to release the energy which had been stored during the charging operation. 'In other words, once the ratchet wheel has been rotated by operation of the re 'ciprocating pawls 59 and '60 in a counterclockwise direction beyond its top dead-center position, the output element 43- is no longer able to restrain downward movement of the spring retaining member 35. The release of energy stored in spring 30 closes the circuit breaker through the operation of the connected load operating shaft 39 and the breaker closing mechanism described hereinbefore, and at the same time the ratchet wheel 40 is rotated further in a counterclockwise direction and returned to its first or initial position shown in FIG. 2.

The ratchet wheel 40, which is driven from the top dead-center position toward its first position in response to the release of closing spring energy, will experience overtravel because of the inertia of the moving parts. In other words, the ratchet wheel rotates in a counterclockwise direction beyond its initial position (FIG. 2) at the conclusion of a breaker closing operation. This results in a clockwise torque being applied to the ratchet wheel by the closing spring 30 acting through the spring retaining member 35 and the eccentric output element 43, and consequently the wheel 40 is driven backwards in a clockwisedirection to its initial position. Again the inertia of the moving parts tends to cause overtravel, but such overtravel in the clockwise direction is prevented by blocking l means which will now be described.

the ratchet wheel 40. The edge of the guide member 74-,

wise movement of the ratchet wheel 40, which movement follows overtravel of the wheel at the conclusion of a breaker closing operation, when the wheel has attained its initial position. This protects pawl 59 and the first peripheral tooth 51 from damage which might occur if the abrupt interengagement of these members were used to stop such clockwise movement of the ratchet wheel. A portion 82 of the edge of the guide member 74 is so relieved that the blocking finger 78 is held out of the orbital path' of element 43 until after the leading edge of this element has passed beyond the distal end of the finger during the breaker closing operation, and in this manner the possibility of misoperation of the blocking means caused by rebounding thereof has been minimized.

In FIG. 5 a modified construction of theratchet wheel 40 is illustrated. The FIG. 5 ratchet 'wheel diliers from the ratchet wheel shown in FIGS. 2-4 in that an additional six peripheral teeth 83-88 have been formed therein. Three of these additional teeth 83, 8S and 87 are grouped with the odd-numbered set of peripheral teeth 51, 53, 55 and 57 for engagement by pawl 59, while the other three additional teeth 84, 86 and 88 are grouped with the even-numbered set of teeth 52, 54, 56 and 58 for engagement by pawl 60. These extra ratchet teeth enable the circuit breaker to be slowly closed in order to check the contact wipe adjustment or to facilitate field assembly of new switch contacts.

To utilize the above-mentioned slow-closing feature, the ratchet mechanism incorporating the FIG. 5 ratchet wheel is operated by pumping the operating handle 63 in the manner described hereinbefore. However, near the conclusion of a spring charging operation, and before the ratchet wheel is driven beyond its top dead-center position, the operator must pause to insert a removable pin (not shown) into a hole 89 located in the spring guide rod 36 at its upper end. As can be seen in FIG. 1, at this point the spring 30 is so compressed that the hole 89 in rod 36 has become exposed above an integral plate 90 of the springs supporting bracket 31 The pin inserted in hole 89 coacts with plate 9|) and rod 36 to interconnect the upper bracket 31 and the lower spring retaining member 35 in a manner which prevents elongation of the closing spring 30. Hence the spring will not release any stored energy upon subsequent movement of which is disposed adjacent to the blocking finger 78, is

slidably engaged by a lateral projection 81 of the finger thereby to determine the position of the finger 78 as the ratchet wheel rotates. This construction is shown in :FIGS. 2, 3 and 4. It is apparent that the finger 78 is so inclined with respect to the orbital path of element 43 that the ratchet wheel rotates without interference in a counterclockwise direction, While clockwise movement of the wheel .from its initial'position (FIG. 2) will be blocked by the abutting engagement between element 43 the ratchet wheel 40 beyond its top dead-centerrposition. The circuit breaker can now be slowlyclosed by continued pumping of the manual operating handle 63.

In response to the next three oscillations of the operating handle 63, the reciprocating pawls 59 and 60 sequentially engage the additional ratchet teeth 83-88 thereby advancing the ratchet Wheel through approximately degrees in a step-by-step manner. By this action the ratchet wheel is returned to its initial position, and its eccentric output element '43- forces the spring retaining member 35 downwardly to its lowest position. As a result, the load operating shaft 39 and hence the closing cam 25 are rotated in a clockwise direction, as viewed in FIG. 1, and the switch arm 14 is actuated by the cir- "cuit breaker operating mechanism to carry the movable -switch contact 12 slowly to its closed circuit position. During this operation the entire closing spring assembly moves downwardly as a unit, with pin 32 of bracket 31 riding in the vertical slot 33 formed in the circuit breaker frame member 34.

During a regular maintenance or inspection routine an operator may stop the slow-closing operation before its conclusion, so as to inspect the partially closed switch contacts or the like, and then reopen the breaker by depressing a trip button (not shown) located on the breaker escutcheon 62. In the event that the operating handle 63 of the ratchet mechanism had been left in its raised position when the slow-closing operation was stopped, the bias spring 64 acting on shaft 61 will serve to hold the handle in this position and prevent its sudden return to its lowered, normal position upon subsequent tripping of the circuit breaker. This feature of my invention prevents possible injury to the hand of the operator when he depresses the trip button.

While I have shown and described a preferred form of my invention by way of illustration, many modifications will occur to those skilled in the art. I therefore contemplate by the claims which conclude this specification to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by United States Letters Patent is:

1. in an electric circuit breaker: a pair of separable switch contacts; a movable switch arm disposed to move one of the switch contacts from an open circuit position to a closed circuit position; stored energy actuating means for the switch arm comprising a spring and an arcuately movable spring retaining member associated therewith, said member being operatively coupled to the switch arm for actuating the switch arm in response to release of energy stored in the spring; and a ratchet mechanism for charging the stored energy actuating means comprising a rotatable ratchet wheel having an eccentric output element orbitally movable in a plane which intersects the plane of arcuate movement of the spring retaining member, said output element being connected to said spring retainin member by means including a bearing having a spherical camming surface, whereby the spring retaining member is moved and energy is stored in the spring in response to rotation of the wheel, said mechanism including at least one pawl for rotating the ratchet wheel and an oscillatory operating member for the pawl.

2. In an electric circuit breaker: a pair of separable switch contacts; a movable switch arm disposed to move one of the switch contacts from an open circuit position to a closed circuit position; stored energy actuating means, including a spring, operatively coupled to the switch arm; and means for charging the stored energy actuating means comprising a rotatable ratchet wheel connected to said spring to stress the spring upon rotation of the wheel, the wheel having two sets of peripheral teeth disposed in side-by-side relationship thereon, a pair of reciprocating pawls disposed to engage the two sets of teeth, respectively, a pair of disc-like guide members on the wheel disposed at opposite sides of one of the two sets of peripheral teeth to define therewith an annular track in which the associated pawl engages said one set of teeth, and an oscillatory handle operatively connected to both lb of the pawls, whereby the wheel is advanced in a stepby-step manner by the alternate actions of said pawls upon repeated oscillations of said handle.

In an electric circuit breaker: a pair of separable switch contacts; a movable switch arm disposed to move one of the switch contacts from an open circuit position to a closed circuit position; stored energy actuating means, including a spring, operatively coupled to the switch arm; and a ratchet mechanism for charging the stored energy actuating means, said ratchet mechanism including a ratchet wheel for stressing said spring upon rotation thereof, first and second reciprocating pawls each of which is disposed to rotate the wheel upon operation thereof, an oscillatory operating handle for the pawls, said wheel being partially rotated by the first pawl in response to movement of the handle from a first position to a second position and being further rotated by the second pawl in response to the handle being returned from its second position to its first position, and means biasing the handle to yieldably oppose movement of the handle away from said first and second positions.

4. In an electric circuit breaker: a pair of separable switch contacts; a movable switch arm disposed to move one of the switch contacts from an open circuit position to a closed circuit position; and a ratchet mechanism for actuating the switch arm, said ratchet mechanism including a rotatable ratchet wheel operatively coupled to the switch arm, first and second reciprocating pawls each of which is disposed to rotate the wheel upon operation thereof, an oscillatory operating handle for the pawls, said wheel being partially rotated by the first pawl in response to movement or" the handle from a first position to a second position and being further rotated by the second pawl in response to the handle being returned from its second position to its first position, and bidirectionally effective bias means connected to the handle to yieldably oppose movement of the handle away from said first and second positions.

5. The electric circuit breaker of claim 4 in which the bidirectionally eifective bias means comprises a toggleaction spring.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN AN ELECTRIC CIRCUIT BREAKER: A PAIR OF SEPARABLE SWITCH CONTACTS; A MOVABLE SWITCH ARM DISPOSED TO MOVE ONE OF THE SWITCH CONTACTS FROM AN OPEN CIRCUIT POSITION TO A CLOSED CIRCUIT POSITION; STORED ENERGY ACTUATING MEANS FOR THE SWITCH ARM COMPRISING A SPRING AND AN ARCUATELY MOVABLE SPRING RETAINING MEMBER ASSOCIATED THEREWITH, SAID MEMBER BEING OPERATIVELY COUPLED TO THE SWITCH ARM FOR ACTUATING THE SWITCH ARM IN RESPONSE TO RELEASE OF ENERGY STORED IN THE SPRING; AND A RATCHET MECHANISM FOR CHARGING THE STORED ENERGY ACTUATING MEANS COMPRISING A ROTATABLE RATCHET WHEEL HAVING AN ECCENTRIC OUTPUT ELEMENT ORBITALLY MOVABLE IN A PLANE WHICH INTERSECTS THE PLANE OF ARCUATE MOVEMENT OF THE SPRING RETAINING MEMBER, SAID OUTPUT ELEMENT BEING CONNECTED TO SAID SPRING RETAINING MEMBER BY MEANS INCLUDING A BEARING HAVING A SPHERICAL CAMMING SURFACE, WHEREBY THE SPRING RETAINING MEMBER IS MOVED AND ENERGY IS STORED IN THE SPRING IN RESPONSE TO ROTATION OF THE WHEEL, SAID MECHANISM INCLUDING AT LEAST ONE PAWL FOR ROTATING THE RATCHET WHEEL AND AN OSCILLATORY OPERATING MEMBER FOR THE PAWL. 